Dear Tzyy-Hong,
If you would like to modify the security settings of the images used in ZeD 1.6.5 you should first open the corresponding BeeKit solution file located in folder: C:\Program Files (x86)\Freescale\ZeD 1.6.5\BeeKitSolutionFiles.
In this case it would be the ZigBeeHcApps_TWR_KW24D512_CB401.bksln or, ZigBeeHcApps_TWR_KW24D512_CB400.bksln depending in the codebase you have in BeeKit. Once open, you may see all of the projects in the right side under “Project explorer”, see image below:

There you may click on “BeeStack” and change the stack profile to “No security with mesh routing – Stack Profile 2”.
IMPORTANT: Use this only for testing purposes. Real ZHA application may require security settings.
Regards,
AngelC